header {
  position: relative;
  height: 420px;
  padding: 150px 0 80px;
  background-color: $blue;
  text-align: center;
}

.mark,
.logo,
.tagline {
  display: block;
  margin: 0 auto;
  @include hide-text;
}

.mark {
  z-index: 10;
  position: absolute;
  left: 50%;
  bottom: -21px;
  @include size(77px 89px);
  margin-left: -38px;
  background: url("../images/mark.svg") center center no-repeat;
}

.logo {
  @include size(619px 47px);
  margin-bottom: 40px;
  background: url("../images/logo.svg") center center no-repeat;

  @media only screen and (max-width: 650px) {
    @include size(280px 21px);
    background-size: 280px 21px;
  }
}

.tagline {
  @include size(475px 19px);
  margin-bottom: 20px;
  background: url("../images/tagline.svg") center center no-repeat;

  @media only screen and (max-width: 650px) {
    @include size(240px 35px);
    margin-bottom: 30px;
    background-image: url("../images/tagline-mobile.svg");
    background-size: 240px 35px;
  }
}

.down {
  position: relative;
  display: block;
  @include hide-text;
  @include size(26px 33px);
  margin: 0 auto;

  @media only screen and (max-width: $mobile) {
    display: none;
  }

  &::before,
  &::after {
    content: "";
    position: absolute;
    left: 0;
    display: block;
    @include size(26px 13px);
    background: url("../images/down.svg") center center no-repeat;
  }

  &::before {
    @include animation(arrowBefore 1s ease-in-out infinite);
    top: 11px;
  }

  &::after {
    @include animation(arrowAfter 1s ease-in-out infinite);
    @include animation-delay(0.125s);
    top: 13px;
  }
}

.contribute {
  position: absolute;
  top: 0;
  right: 0;
  @include size(160px);
  @include hide-text;
  background: url("../images/contribute.svg") center center no-repeat;

  @media only screen and (max-width: $mobile) {
    display: none;
  }
}

@include keyframes(arrowBefore) {
  0% {
    @include transform(translateY(3px));
  }

  50% {
    @include transform(translateY(6px));
  }

  100% {
    @include transform(translateY(3px));
  }
}

@include keyframes(arrowAfter) {
  0% {
    @include transform(translateY(14px));
  }

  50% {
    @include transform(translateY(17px));
  }

  100% {
    @include transform(translateY(14px));
  }
}

.mobile-about {
  display: none;
  z-index: 10;
  position: absolute;
  top: 0;
  left: 0;
  @include size(100% 40px);
  padding-top: 10px;
  background-color: #393d43;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: 3px;
  color: white;
  transition: all 300ms;
  cursor: pointer;

  &:hover {
    background-color: #535a60;
  }

  @media only screen and (max-width: $mobile) {
    display: block;
  }
}
